Status of Phytophthora diseases in Nagpur mandarin orchards of Vidarbha region

Abstract

In central India the major cause of citrus decline is supposed to be because of Phytophthora causing diseases in citrus. The pathogen attack citrus plants right from nursery causing damping off of seedlings, decay of fibrous roots, crown rot, collar rot, foot rot and gummosis in mature orchards. Nagpur mandarins face short life span and low productivity because of these three species of Phytophthora viz. P. parasitica, P. citrophthora and P. palmivora. An intensive rapid roving survey of selected mandarin orchards was conducted during the year 2016 and 2017 to access incidence and intensity of Phytophthora diseases (root rot and gummosis). Total 83 orchards were surveyed during peak period of diseases (August to November) by using modified disease rating scale (0-9). According to rapid roving survey of root rot in selected orchards, pooled data indicate similar disease progress with root rot incidence in the range of 10.42 to 62.50% and intensity from 1.62 up to 23.48%. In case of gummosis pooled data indicate similar trend of disease development with gummosis incidence in the range of 14.58 to 64.58% and intensity in between 2.08 to 19.91%.